This paper introduces a remotely operated robotic system being developed for urban search and rescue. The developed QuadTrack-I has four modular track arms which can be driven independently to get a traction force. The modular track arms can also be rotated with respect to their arm axes to lift the body or step over larger obstacles. The QuadTrack-I can carry a small articulated robot to collapsed areas where victims could be under rubble. QuadTrack-II is also under development to increase the traction power and mobility of QuadTrack-I. This paper describes the structures of the robots and shows some experimental results.